\begin{tikzpicture}
    \tkzDefPoints{0/0/A, 4/0/B, 1/2.2/C,  3.5/1.5/D}

    \tkzDrawPoints(A,B,C,D)
    \tkzLabelPoints[left](A,C)
    \tkzLabelPoints[right](B,D)

    % \tkzDefLine[mediator](A,C) \tkzGetPoints{a}{c}
    % \tkzDefLine[mediator](B,D) \tkzGetPoints{b}{d}
    % \tkzDrawSegments(a,c  b,d)
    % \tkzInterLL(a,c)(b,d)  \tkzGetPoint{P}
    % \tkzDrawPoints(P)
    % \tkzLabelPoints[below](P)
\end{tikzpicture}

